Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
accel/rocket: fix NULL dereference and integer overflow in rocket_job_push()
rocket_job_push() allocates a temporary array to hold all input and output GEM object pointers:
bos = kvmalloc_array(job->in_bo_count + job->out_bo_count, sizeof(void *), GFP_KERNEL); memcpy(bos, job->in_bos, job->in_bo_count * sizeof(void *)); memcpy(&bos[job->in_bo_count], job->out_bos, …);
Two bugs exist:
-
Missing NULL check: if kvmalloc_array() fails, bos is NULL and the subsequent memcpy() dereferences it, causing a kernel NULL pointer dereference.
-
Integer overflow: in_bo_count and out_bo_count are both u32, set directly from userspace-supplied in_bo_handle_count and out_bo_handle_count with no prior validation. Their sum is computed in u32 arithmetic and can wrap to a smaller value, causing the allocation count passed to kvmalloc_array() to be smaller than intended. Subsequent uses still operate on the original counts when copying and locking objects, which may lead to out-of-bounds accesses on the temporary array.
Fix by using check_add_overflow() to detect count overflow before the allocation, and adding a NULL check on the allocation result.
Details
- Affected product:
- Debian 10 ELS , Debian 11 ELS
- Affected packages:
- linux @ 4.19.0 (+1 more)